A study of l-leucine, l-phenylalanine and l-alanine transport in the perfused rat mammary gland: possible involvement of LAT1 and LAT2 |
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Authors: | DB Shennan DT CalvertMT Travers Y KudoCAR Boyd |
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Institution: | a Hannah Research Institute, Ayr Scotland, KA6 5HL, UK b Department of Human Anatomy and Genetics, University of Oxford, Oxford, OX1 3QX, UK |
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Abstract: | The transport of l-leucine, l-phenylalanine and l-alanine by the perfused lactating rat mammary gland has been examined using a rapid, paired-tracer dilution technique. The clearances of all three amino acids by the mammary gland consisted of a rising phase followed by a rapid fall-off, respectively, reflecting influx and efflux of the radiotracers. The peak clearance of l-leucine was inhibited by BCH (65%) and d-leucine (58%) but not by l-proline. The inhibition of l-leucine clearance by BCH and d-leucine was not additive. l-leucine inhibited the peak clearance of radiolabelled l-leucine by 78%. BCH also inhibited the peak clearance of l-phenylalanine (66%) and l-alanine (33%) by the perfused mammary gland. Lactating rat mammary tissue was found to express both LAT1 and LAT2 mRNA. The results suggest that system L is situated in the basolateral aspect of the lactating rat mammary epithelium and thus probably plays a central role in neutral amino acid uptake from blood. The finding that l-alanine uptake by the gland was inhibited by BCH suggests that LAT2 may make a significant contribution to neutral amino acid uptake by the mammary epithelium. |
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Keywords: | Mammary gland l-leucine" target="_blank">l-leucine l-phenylalanine" target="_blank">l-phenylalanine l-alanine" target="_blank">l-alanine |
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